<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        #box{
            width: 200px;
            height: 200px;
            background: red;
            margin: 100px auto;
        }
    </style>
</head>
<body>
<input type="button" value="切换效果" id="btn">
<div id="box"></div>
</body>
</html>
<script src="js/jquery-1.10.1.js"></script>
<script>
    $(function () {
        $("#btn").click(function () {
            $("#box").fadeToggle("slow");
        })
    })
</script>